Cementing tool

ABSTRACT

A cementing tool for providing multiple stage cementing of an oil well has an outer case, a closing sleeve located concentrically therein, upper and lower adapters, a releasing sleeve, an opening sleeve, and a sleeve retainer located within the closing sleeve.

O United States Patent 1 91 1111 3,768,556

Baker 1 Oct. 30, 1973 CEMENTING TOOL 3,527,297 9 1970 Todd 166/1542,928,470 3/1960 Baker... 166/154 [75] Inventor. Eugene E. Baker,Duncan, Okla. 2,998,075 8/1961 Clark 66/154 x [73] Assignee: HalliburtonCompany, Dun 3,228,473 1/1966 Baker 166/154 Oka 3,306,365 2/1967Kammerer 166/154 X [22] filed: May 1972 Primary Examiner-David H. Brown[21] Appl. No.: 254,630 AttorneyJohr1 H. Tregoning et a1.

[52] U.S. Cl. 166/154, 166/224 [57] ABSTRACT [51] Int. Cl E211) 33/16[58] Field of Search ..l66/152156, 224 A cememmg tool for Provldmgmumple Stage cement ing of an oil well has an outer case, a closingsleeve located concentrically therein, upper and lower adapt- [56]References cued ers, a releasing sleeve, an opening sleeve, and a sleeveUNITED STATES PATENTS retainer located within the closing sleeve.

, 2,659,438 11 1953 Schnitter 1661154 9 Claims, 6 Drawing FiguresPAIENTEnnm 30 I975 3.768556 SHEET 20F 3 FIG. 4

CEMENTING TOOL BACKGROUND OF THE INVENTION In preparing oil well boreholes for oil and/or gas production a most important step involves theprocess of cementing.

Basically, oil well cementing is a process of mixing a cement-waterslurry and pumping it down through steel 7 casing to critical pointslocated in the annulus around the casing, in the open hole below, or infractured formations.

Cementing a well protects possible productive zones behind the casingagainst salt water flow and protects the casing against corrosion fromsubsurface mineral waters and electrolysis from outside.

Cementing eliminates the danger of fresh drinking water and recreationalwater supply strata from being contaminated by oil or salt water flowthrough the bore hole from formations containing those substances. Itfurther prevents oil well blowouts and fires caused by high pressure gaszones behind the casing and prevents collapse of the casing from highexternal pressures which can build up underground.

A cementing operation for protection against the above describeddownhole conditions is called primary cementing. Secondary cementingincludes the cementing processes used on a well during its productivelife, such as remedial cementing and repairs to existing cemented areas.The present invention is generally useful in primary cementing.

In the early days of oil field production, when wells were allrelatively shallow, cementing was accomplished by flowing the cementslurry down the casing and back up the outside of the casing in theannulus between the casing and the bore hole wall.

As wells were drilled deeper and deeper to locate petroleum products, itbecame difficult to successfully cement the entire well from the bottomof the casing and multiple stage cementing was developed to allow theannulus to be cemented in separate stages, beginning at the bottom ofthe well and working up.

This process is achieved by placing cementing tools, which are primarilyvalved ports, in the casing or between joints of casing at one or morelocations in the bore hole, flowing through the bottom of the casing, upthe annulus to the lowest cementing tool in the well,

closing off the bottom, opening the cementing tool, and

then flowing through the cementing tool up the annulus to the next upperstage and repeating this process until all stages are completed.

Cementing tools used for multi-stage cementing usually have two sleeves,both of which are usually shearpinned initially in an upper position,closing the cementing ports in the tool. To open the cementing ports aplug is flowed down the casing and seated on the lower sleeve. The fluidpressure is then increased in the casing until sufficient force isdeveloped on the plug and sleeve to shear the shear pins and move thelower sleeve to the position uncovering the cementing ports. Cement isthen flowed down the casing and out the open ports into the annulus.When the predetermined desired amount of cement has been flowed into theannulus, another plug is placed in the casing behind the cement andflowed down the casing to seat on the upper sleeve. The pressure isincreased on the second plug until the shear pins holding it are severedand the upper sleeve is moved down to close the cementing ports.

The difficulty arises when the second plug is flowed in to close theports and as the ports begin to close a hydraulic lock occurs betweenthe two plugs due to the incompressibility of the cement slurry trappedbetween them and the second sleeve does not travel the sufficientdistance to close and seal off the ports. Thereafter when pressure inthe casing is relieved, the upper sleeve may float back open and allowthe cement to reverse flow from the annulus back into the casing.

Another difficulty inherent in the prior art devices is that the lowersleeve or the upper sleeve or both may become actuated prematurelycausing a misrun and necessitating a large amount of time and expense tocorrect.

The present invention overcomes these difficulties by providing acementing tool with positive opening and closing action, with a lockingdevice to prevent premature opening, locking means to prevent openingafter the cementing has been completed, and means to prevent a hydrauliclock between the opening and closing plugs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectionalview of the cementing tool of this invention.

FIG. 2 is an isometric view of theclosing sleeve of the cementing toolof FIG. 1.

FIGS. 3 through 6 are schematic diagrams showing the method of operationof this tool.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, thecementing tool 1 has a tubular outer case 2 to which is attached upperadapter 3 and lower adapter 4. These can be connected together by anyconventional means such as welding at 5 and 6 as well as threadedconnections at 7 and 8. Upper adapter 3 and lower adapter 4 may bethreaded at their extreme ends or otherwise arranged to fit betweenstandard sections of easing or other pipe or can be adapted to be weldedin place in the casing where the casing must be cut and the cementingtool inserted therein.

Outer case 2 is a cylindrical tubular housing having an inner diameterlarger than the inner diameter of the casing or pipe string in which itis inserted. It is made of a tough durable material such as steel orstainless steel. Passing through the wall of case 2 are two or moreports 9; Passing circumferentially around the annular recess l0.

Outer case 2 also contains inner annular recess 11 having sloping walls12 and 13. Also located in the case 2 is sloping wall 14 which, inconjunction with wall 12, forms inner annular shoulder 15.

Located near the bottom of outer case 2 is a third inner annular recess16 having a perpendicular face 17 and a sloping wall 18.

Closing sleeve 20 is a tubular cylindrical sleeve located concentricallywithin case 2 and having an outer diameter slightly less than that ofcase 2 so that the sleeve 20 can slide within case 2 without needingundue force to overcome friction between the walls. Sleeve 20 has aninner diameter substantially equal to that of the casing or pipe stringin which the cementing tool is located, and is also made of a toughdurable material such as steel or stainless steel.

Closing sleeve has two or more ports 19 passing therethrough preferablyaligned with ports 9 of case 2. Sleeve 20 also has at its upper end, acollet ring 21 formed by outer annular ridge 22 formed on sleeve 20 andinner annular recess 23 cut in it. Collect ring 21 is comprised ofcollet fingers 24 (FIG. 2) formed in the upper end of sleeve 20 byequispaced machined grooves 25 cut into sleeve 20 extending throughannular ridge 22 and recess 23.

One or more annular recesses 26 located circumferentially about theexterior of sleeve 20, above and below ports 19, retain elastomeric sealmeans 27, 27a and 27b which provide a fluidic seal between sleeve 20 andcase 2, above and below ports 9 and 19.

Sleeve 20 also has an external circumferential grooved channel not shownpassing around the sleeve and intersecting ports 19. This channel andrecess 10 in case 2 provide fluid communication between ports 9 and 19should sleeve 20 become rotated within case 2 during the cementingoperation.

Channel 29 in sleeve 20 contains expanding lock rings 30 which arecompressed into channel 29. When channel 29 moves adjacent to recess 16in case 2 the lock rings 30 expand into recess 16, and partially out ofchannel 29 and because of abutment with face 17 and channel 29, sleeve20 cannot move back upward within case 2. This provides the lockedclosed feature of the tool which occurs after cementing has beencompleted. The collet fingers 21 have ridge 22 abutted against face 14of case 2 to prevent premature movement of sleeve 2 before cementing iscompleted through the tool.

Sleeve 20 also has an inner annular recess 31 located below ports 19 andhaving perpendicular faces 32 and 33.

Located concentrically within closing sleeve 20 are releasing sleeve 34,opening sleeve 35 and sleeve retainer 36. Opening sleeve 35 is acylindrical collar snugly fitting within closing sleeve 20, and having abeveled plug seat 37, and is initially placed to cover ports 19 and 9.Opening sleeve 35 is held in closed position over ports 9 and 19 byshear pins 38 threadedly engaged in closing sleeve 20 and opening sleeve35 in the same plane as ports 19 and 9. The shear pins have been rotatedin FIG. 1 for purposes of illustration only.

Opening sleeve 35 also has annular recesses 40 located above and belowshear pins 38 for receiving circular seals 41 which provide fluidsealing between opening sleeve 35 and closing sleeve 20. Opening sleeve35 also has recess 42 passing circumferentially around it to receiveexpanding lock ring 43 which is compressed into recess 42 and which ringis capable of expanding partially into recess 31 of sleeve 20 whenrecess 42 is aligned with recess 31. This provides a locking arrangementbetween sleeve 35 and sleeve 20 when sleeve 35 has been moved into theopen-port cementing position.

Located directly above opening sleeve 35 and abutting the upper face 44of sleeve 35 is releasing sleeve 34 which is a cylindrical tubularsleeve having a narrowed skirt 45 at its lower end and raised shoulder46 at its upper end. Narrowed skirt 45 in conjunction with closingsleeve 20 forms annular area 47 communicating from the lower end 48 ofskirt 45 to sloping face 49 of the releasing sleeve.

Raised shoulder 46 is an annular shoulder contacting collet fingers 24maintaining them in their outward position in abutment with case 2 atshoulder 14 which prevents closing sleeve 20 from moving downward andclosing off ports 9. Releasing sleeve 34 is attached initially toclosing sleeve 20 by shear pins 50, passing through sleeve 20 and sleeve34. Circular seals 51 in annular recesses in releasing sleeve 34 providea fluidic seal between the upper part of sleeve 34 and the closingsleeve 20. Plug seat 52 is formed on the upper inner edge of sleeve 34by beveling the inner edge of the sleeve end.

Sleeve retainer 36 is a circular ring fixedly attached to the lowerinterior end of closing sleeve 20. As shown, it is attached by a snuglymatching threaded connection 53. Retainer 36 is adapted and locatedessentially to abut opening sleeve 35 in its lowermost position andfurther aid lock ring 43 in preventing extreme downward movement ofopening sleeve 35 in closing sleeve 20. Sleeve retainer 36 also providesan additional force transmitting means from opening sleeve 35 to closingsleeve 20.

It is desirable to make releasing sleeve 34, opening sleeve 35, andsleeve retainer 36 of some easily drilled material such as aluminum,aluminum alloy, brass, bronze, or cast iron, so that these parts may beeasily drilled out of the tool after cementing is completed, therebyproviding a fully opened passage through the cementing tool.

In typical operation, referring now to FIGS. 3 through 6, the cementingtool 1 is placed in the casing or pipe string 55 before it is run in thehole. It may be inserted between standard threaded sections of the pipeat the desired locations of cementing stages to be I performed. A numberof cementing stages are possible with this tool as long as eachcementing tool in the pipe string has a smaller inner diameter than thecementing tool immediately above it.

After the pipe string or casing is in place in the hole, the first orlowermost stage of cementing may be accomplished through the bottom ofthe pipe string56 and up the annulus 57. A wiper plug 58 is insertedbehind the first stage of cement slurry, and displacing fluid ofapproximately the same specific gravity as the cement slurry is pumpedbehind the wiper plug to displace the cement from the pipe string.

After a precalculated amount of displacing fluid, sufficient to fill thepipe string from the bottom 56 to the next upper cementing tool, hasbeen pumped into the pipe string, an opening plug 54 is inserted in thepipe and flowed'down to seat on plug seat 37 of opening sleeve 35,fluidically sealing off the opening through the cementing tool.Alternatively, a bomb or ball can be dropped through the fluid in thepipe to seal it off. A precalculated amount of cementslurry sufficientto complete cementing of the second stage, is flowed behind opening plug54.

Pressure sufficient to shear the shear pins 38 is then applied to thecement slurry and fluid in the pipeline, which pressure, acting throughplug 54, shears pins 38 and forces opening sleeve 35 downward, exposingports 19 and 9. Cement then flows through the ports and up the annulus59. The tool is then in the position shown in FIG. 4. Lock ring 42 hasengaged in recess 31 thereby preventing any upward shifting of theopening sleeve in the closing sleeve.

When a precalculated amount of cement sufficient to complete the secondstage has been pumped into the pipe, a closing plug 59 is pumped behindthe cement followed by displacing fluid. Closing plug 59 seats in plugseat 52 closing off the passage therethrough and, when fluidic pressurereaches a predetermined sufficient level on plug 59, the shear pins 50are sheared allowing sleeve 34 to move downward out of abutting contactwith collet ring 21. Recess 47 allows cement trapped between plugs 54and 59 to continue to exit through ports 19 and 9, thereby preventing ahydraulic lock therebetween. Continued pressure on plug 59 forces sleeve34 to its lowermost position with shoulder 60 abutting face 61 of sleeve20.

A sufficient predetermined pressure force transmitted through plug 59then acts downward on sleeve 34, through shoulder 46, abutting face 60of sleeve 34 with face 61 of sleeve 20 thereby transmitting force tosleeve 20, overcoming the spring force in collet fingers 24, andallowing collet ring 21 to be compressed inward, moving past shoulder 14and downward there from. This in turn moves ports 19 downward and out ofalignment with ports 9 and passes seals 27b below ports 9 therebyfiuidically sealing ports 9 from the interior bore of the cementingtool 1. At this point lock rings 30 in recess 29 have come adjacent torecess 16 and expanded part of the way thereinto thereby preventing anymovement of sleeve 20 back upwards. Downward travel of sleeve 20 inhousing 2 is limited by lower end 62 of sleeve 20 abutting upper end 63of loweradapter 4. It should be noted that before closing sleeve 20 ismoved downward, plugs 54 and 59 have become stationary with respect toeach other and there is no more possibility of a hydraulic lock betweenthem.

Closing ports 9 completes this cementing stage and the next cementingstage can begin. After the final stage is completed the bore passageobstructions consisting of sleeves 34, 35, and 36, plugs 54 and 59, andthe cement between plugs 54 and 59, can be easily drilled out leavingthe bore passage completely open and unobstructed for subsequentoperations therethrough.

Although a specific preferred embodiment of the present inventionhasbeen described in the detailed description above, the description isnot intended to limit the invention to the particular forms orembodiments disclosed herein, since they are to be recognized asillustrative rather than restrictive and it will be obvious to thoseskilled in the art that the invention is not so limited. For example thecollet ring locking device of this invention could be replaced with asnap ring type locking device. Also, where seals having polygonal crosssections are revealed, it would be obvious to substitute O-ring seals orother type seal means therefor. Likewise, other shear means than shearpins could be used advantageously. The invention is declared to coverall changes and modifications of the specific example of the inventionherein disclosed for purposes of illustration, which do not constitutedepartures from the spirit and scope of the invention.

What is claimed is:

1. A cementing tool for cementing through a pipe string or casingcomprising: I

a. a tubular housing containing one or more outer cementing portsthrough the wall;

b. means for interposing said tubular housing be tween pipe sections ina string of pipe and attaching said housing to the pipe;

0. a closing sleeve slidably located within said tubular housing andcontaining one or more inner cementing ports through the wall; saidclosing sleevein one position allowing said outer ports and said innerports to communicate therethrough and in a second position isolatingsaid inner ports from said outer ports; said closing sleeve having alarge unrestricted bore therethrough with a relatively constant innerdiameter substantially equivalent to the inner diameter of the pipestring or casing;

d. an opening sleeve slidably located within said closing sleeve andcovering said inner ports in a first position and uncovering said portsin a second position; said opening sleeve having a large unrestrictedbore therethrough of substantially constant diameter and only slightlysmaller in diameter than said closing sleeve;

e. spring means on said closing sleeve engaging said housing, saidspring means adapted to retain said closing sleeve in an open-portposition until sufficient force is applied downward on said sleeve toovercome said spring means;

f. a releasing sleeve slidably located within said closing sleeve andarranged in a first upper position to maintain said spring means engagedin said housing and in a second position to release said spring meansand engage said closing sleeve to move it downward; said releasingsleeve having a large unrestricted bore therethrough with asubstantially constant inner diameter which is only slightly smallerthan the diameter of the pipestring or casg. a sleeve retainer fixedlylocated within said closing sleeve and adapted to limit downwardmovement of said opening sleeve; said retainer having an openunrestricted bore therethrough substantially equal to that of saidopening sleeve;

h. first shear means contained in said closing sleeve and said openingsleeve, attaching said opening sleeve to said closing sleeve andarranged to maintain said opening sleeve covering said inner ports;

i. second shear means contained in said releasing sleeve and saidclosing sleeve and attaching said releasing sleeve to said closingsleeve;

j. means for selectively shearing said first and second shear meansfurther comprising first activating means and second activating means,said first activating means further adapted to fluidically seal the boreof said opening sleeve and said second activating means adapted tofluidically seal the bore of said releasing means, said first activatingmeans arranged to shear said first shear means and said secondactivating means arranged to shear said second shear means; and

k. recess means in the exterior surface of the lower end of saidreleasing sleeve, said recess means arranged toprevent fluid lockbetween said first activating means and said second activating means byfluidically communicating between said outer and inner cementing portsand the area trapped between said first and second activating means.

2. The cementing tool of claim 1 further comprising first spring lockingmeans between said closing sleeve and said housing for preventing upwardmovement of said closing sleeve in said housing after said closingsleeve has been moved into closed-port position, and second springlocking means between said opening sleeve and said closing sleeve forpreventing upward movement of said opening sleeve in said closing sleeveafter said opening sleeve has moved downward into open-port relationshipin said closing sleeve.

3. The apparatus of claim 2 further comprising seal means between saidclosing sleeve and said housing, seal means'between said releasingsleeve and said closing sleeve, and seal means between said openingsleeve and said closing sleeve, said seal means between said closingsleeve and said housing comprising relatively elongated cylindricalcircular seal means of elastomeric material.

4. The apparatus of claim 1 wherein said first activating meanscomprises a plug member adapted to be flowed into the pipe stringthrough said releasing sleeve, and seated on said opening sleeve, saidopening sleeve having a beveled inwardly and upwardly facing plug seatarranged to receive said plug member in fluidically sealing arrangement;said plug member having a plurality of resilient wiper elements thereoncapable of engaging the casing wall and further having a beveled sealingsurface located thereon to sealingly engage said opening sleeve plugseat; and said second activating means comprises a second plug memberadapted to be flowed into the pipe string to seat on said releasingsleeve, with said releasing sleeve having a beveled inwardly andupwardly facing plug seat arranged to receive said plug member influidically sealing arrangement; said second plug member having aplurality of resilient wiper elements thereon capable of engaging thecasing wall and further having a beveled sealing surface located thereonto sealingly engage said releasing sleeve plug seat; and said plug seatin said opening sleeve having smaller diameter than said plug seat insaid releasing sleeve.

5. The apparatus of claim 4 wherein said housing further comprises aninner annular recess intersecting and providing fluid communicationbetween said outer ports, and said closing sleeve further comprises anouter circumferential channel intersecting and providing fluidcommunication between said inner ports, said inner annular recess andsaid outer circumferential channel arranged to conjoin and provide fluidcommunication between said inner ports and said outer ports should theybecome radially misaligned when said closing sleeve is in the uppermost,open-port position and said opening sleeve is in its lowermost,open-port position.

6. A cementing tool adapted to be interposed between adjoining sectionsof pipe and having an inner bore portion, comprising:

a. a cylindrical hollow outer casing having a bore portion passinglongitudinally therethrough and one or more outer cementing portspassing through the wall thereof;

b. first sleeve means mounted within said outer casing and having one ormore inner cementing ports arranged to communicate with said outer portsin a first position of said first sleeve means and said first sleevemeans adapted to be movable to a second position wherein said outerports are fluidically sealed from the bore portion of said cementingtool;

c. second sleeve means located within said first sleeve means, attachedto said first sleeve means by first shear means, and arranged to coversaid inner and outer ports in a first, closed position and arranged touncover said ports in a second open position;

(1. third sleeve means also located within said first sleeve means andattached to said first sleeve means by second shear means;

e. spring means located on said first sleeve means between said thirdsleeve means and said casing for maintaining said first sleeve means insaid first position of said first sleeve means, said spring meansadapted to be released by said third sleeve means when said third sleevemeans moves to a lower position within said first sleeve means;

f. means for engaging said second sleeve means and for shearing saidfirst shear means;

g. means for engaging said third sleeve means, moving said third sleevemeans downward, shearing said second shear means, and releasing saidspring means;

h. locking spring means between said first sleeve means and said casingand arranged to mechanically lock said first sleeve means in itslowermost position within said casing;

i. locking means between said second sleeve means and said first sleevemeans and adapted to lock said second sleeve means in its lowermostposition in said first sleeve means;

j. seal means located between said casing, said first sleeve means, saidsecond sleeve means, and said third sleeve means, and arranged tofluidically seal between the walls thereof;

k. retaining means located within said first sleeve means and adapted tofurther limit downward travel of said second sleeve means in said firstsleeve means; and

. fluidic lock prevention means between said first sleeve means and saidthird sleeve means for preventing the trapping of hydraulic pressurebetween said means for engaging said second sleeve means and said meansfor engaging said third sleeve means. I

7. The cementing tool of claim 6 wherein said spring means comprises acollet ring formed of collet fingers extending upwardly from said firstsleeve means, said collet fingers each having an inner and outerprojected shoulder, which said shoulders on said fingers act inconjunction to form a collet ring in abutment with said casing and saidthird sleeve means, and adapted to remain locked in abutment with saidcasing until said third sleeve means is moved downward, out of abutmentwith said collet ring.

8. The cementing tool of claim 7 wherein said means for engaging saidsecond sleeve means and for shearing said first shear means comprises afirst plug member adapted to be pumped into the pipeline under pressure,said second sleeve means having a beveled upper inner edge forming aplug member seat wherein said first plug member seats and fluidicallyseals off said second sleeve means.

9. The cementing tool of claim 8 wherein said means for engaging saidthird sleeve means and for shearing said second shear means comprises asecond plug member having a larger diameter than said first plug memberand also adapted for being pumped into a pipeline under pressure, saidthird sleeve means having a bevameter than said seat in said secondsleeve means, sufficient to allow said first plug member to pass throughsaid third sleeve means relatively unhindered.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated October 301973 Patent No. 3 768 556 Inventoflfl) Euqene E. Baker It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In Claim 9, column 9 at line 3-and line 4, delete [said second plugmember seats and fluidically seals off] Signed and v sealed this 9th dayof April 197E.

(SEAL) Attest:

EDWARD FLFLETCHERJR. C. MARSHALL DANN Attesting Officer" Commissioner ofPatents USCOMM-DC 6037 6-P69 FORM PO-IOSO (10-69) us. covsmmzu-r rum-nusOFFICE: nus o-ass-su.

1. A cementing tool for cementing through a pipe string or casingcomprising: a. a tubular housing containing one or more outer cementingports through the wall; b. means for interposing said tubular housingbetween pipe sections in a string of pipe and attaching said housing tothe pipe; c. a closing sleeve slidably located within said tubularhousing and containing one or more inner cementing ports through thewall; said closing sleeve in one position allowing said outer ports andsaid inner ports to communicate therethrough and in a second positionisolating said inner ports from said outer ports; said closing sleevehaving a large unrestricted bore therethrough with a relatively constantinner diameter substantially equivalent to the inner diameter of thepipe string or casing; d. an opening sleeve slidably located within saidclosing sleeve and covering said inner ports in a first position anduncovering said ports in a second position; said opening sleeve having alarge unrestricted bore therethrough of substantially constant diameterand only slightly smaller in diameter than said closing sleeve; e.spring means on said closing sleeve engaging said housing, said springmeans adapted to retain said closing sleeve in an open-port positionuntil sufficient force is applied downward on said sleeve to overcomesaid spring means; f. a releasing sleeve slidably located within saidclosing sleeve and arranged in a first upper position to maintain saidspring means engaged in said housing and in a second position to releasesaid spring means and engage said closing sleeve to move it downward;said releasing sleeve having a large unrestricted bore therethrough witha substantially constant inner diameter which is only slightly smallerthan the diameter of the pipestring or casing; g. a sleeve retainerfixedly located within said closing sleeve and adapted to limit downwardmovement of said opening sleeve; said retainer having an openunrestricted bore therethrough substantially equal to that of saidopening sleeve; h. first shear means contained in said closing sleeveand said opening sleeve, attaching said opening sleeve to said closingsleeve and arranged to maintain said opening sleeve covering said innerports; i. second shear means contained in said releasing sleeve and saidclosing sleeve and attaching said releasing sleeve to said closingsleeve; j. means for selectively shearing said first and second shearmeans further comprising first activating means and second activatingmeans, said first activating means further adapted to fluidically sealthe bore of said opening sleeve and said second activating means adaptedto fluidically seal the bore of said releasing means, said firstactivating means arranged to shear said first shear means and saidsecond activating means arranged to shear said second shear means; andk. and recess means in the exterior surface of the lower end of saidrEleasing sleeve, said recess means arranged to prevent fluid lockbetween said first activating means and said second activating means byfluidically communicating between said outer and inner cementing portsand the area trapped between said first and second activating means. 2.The cementing tool of claim 1 further comprising first spring lockingmeans between said closing sleeve and said housing for preventing upwardmovement of said closing sleeve in said housing after said closingsleeve has been moved into closed-port position, and second springlocking means between said opening sleeve and said closing sleeve forpreventing upward movement of said opening sleeve in said closing sleeveafter said opening sleeve has moved downward into open-port relationshipin said closing sleeve.
 3. The apparatus of claim 2 further comprisingseal means between said closing sleeve and said housing, seal meansbetween said releasing sleeve and said closing sleeve, and seal meansbetween said opening sleeve and said closing sleeve, said seal meansbetween said closing sleeve and said housing comprising relativelyelongated cylindrical circular seal means of elastomeric material. 4.The apparatus of claim 1 wherein said first activating means comprises aplug member adapted to be flowed into the pipe string through saidreleasing sleeve, and seated on said opening sleeve, said opening sleevehaving a beveled inwardly and upwardly facing plug seat arranged toreceive said plug member in fluidically sealing arrangement; said plugmember having a plurality of resilient wiper elements thereon capable ofengaging the casing wall and further having a beveled sealing surfacelocated thereon to sealingly engage said opening sleeve plug seat; andsaid second activating means comprises a second plug member adapted tobe flowed into the pipe string to seat on said releasing sleeve, withsaid releasing sleeve having a beveled inwardly and upwardly facing plugseat arranged to receive said plug member in fluidically sealingarrangement; said second plug member having a plurality of resilientwiper elements thereon capable of engaging the casing wall and furtherhaving a beveled sealing surface located thereon to sealingly engagesaid releasing sleeve plug seat; and said plug seat in said openingsleeve having smaller diameter than said plug seat in said releasingsleeve.
 5. The apparatus of claim 4 wherein said housing furthercomprises an inner annular recess intersecting and providing fluidcommunication between said outer ports, and said closing sleeve furthercomprises an outer circumferential channel intersecting and providingfluid communication between said inner ports, said inner annular recessand said outer circumferential channel arranged to conjoin and providefluid communication between said inner ports and said outer ports shouldthey become radially misaligned when said closing sleeve is in theuppermost, open-port position and said opening sleeve is in itslowermost, open-port position.
 6. A cementing tool adapted to beinterposed between adjoining sections of pipe and having an inner boreportion, comprising: a. a cylindrical hollow outer casing having a boreportion passing longitudinally therethrough and one or more outercementing ports passing through the wall thereof; b. first sleeve meansmounted within said outer casing and having one or more inner cementingports arranged to communicate with said outer ports in a first positionof said first sleeve means and said first sleeve means adapted to bemovable to a second position wherein said outer ports are fluidicallysealed from the bore portion of said cementing tool; c. second sleevemeans located within said first sleeve means, attached to said firstsleeve means by first shear means, and arranged to cover said inner andouter ports in a first, closed position and arranged to uncover saidports in a second open position; d. third sleeve means also locatedwithin said first sleeve means and attached to said first sleeve meansby second shear means; e. spring means located on said first sleevemeans between said third sleeve means and said casing for maintainingsaid first sleeve means in said first position of said first sleevemeans, said spring means adapted to be released by said third sleevemeans when said third sleeve means moves to a lower position within saidfirst sleeve means; f. means for engaging said second sleeve means andfor shearing said first shear means; g. means for engaging said thirdsleeve means, moving said third sleeve means downward, shearing saidsecond shear means, and releasing said spring means; h. locking springmeans between said first sleeve means and said casing and arranged tomechanically lock said first sleeve means in its lowermost positionwithin said casing; i. locking means between said second sleeve meansand said first sleeve means and adapted to lock said second sleeve meansin its lowermost position in said first sleeve means; j. seal meanslocated between said casing, said first sleeve means, said second sleevemeans, and said third sleeve means, and arranged to fluidically sealbetween the walls thereof; k. retaining means located within said firstsleeve means and adapted to further limit downward travel of said secondsleeve means in said first sleeve means; and l. fluidic lock preventionmeans between said first sleeve means and said third sleeve means forpreventing the trapping of hydraulic pressure between said means forengaging said second sleeve means and said means for engaging said thirdsleeve means.
 7. The cementing tool of claim 6 wherein said spring meanscomprises a collet ring formed of collet fingers extending upwardly fromsaid first sleeve means, said collet fingers each having an inner andouter projected shoulder, which said shoulders on said fingers act inconjunction to form a collet ring in abutment with said casing and saidthird sleeve means, and adapted to remain locked in abutment with saidcasing until said third sleeve means is moved downward, out of abutmentwith said collet ring.
 8. The cementing tool of claim 7 wherein saidmeans for engaging said second sleeve means and for shearing said firstshear means comprises a first plug member adapted to be pumped into thepipeline under pressure, said second sleeve means having a beveled upperinner edge forming a plug member seat wherein said first plug memberseats and fluidically seals off said second sleeve means.
 9. Thecementing tool of claim 8 wherein said means for engaging said thirdsleeve means and for shearing said second shear means comprises a secondplug member having a larger diameter than said first plug member andalso adapted for being pumped into a pipeline under pressure, said thirdsleeve means having a beveled upper inner edge forming a plug memberseat wherein said second plug member seats and fluidically seals offsaid second sleeve means, said plug member seat in said third sleevemeans having a larger inner diameter than said seat in said secondsleeve means, sufficient to allow said first plug member to pass throughsaid third sleeve means relatively unhindered.